Method and System for Centralized Checkout Process

2. The enterprise checkout system of claim 1, wherein the unified payment transaction is associated with at least a first request comprising first request data and a second request comprising second request data, the first request being received from a first tenant interface of the plurality of tenant interfaces and the second request being received from a second tenant interface of the plurality of tenant interfaces, the second tenant interface being different from the first tenant interface.

3. The enterprise checkout system of claim 2, wherein the first tenant interface comprises the point of sale tenant interface and the second interface comprises the digital tenant interface.

4. The enterprise checkout system of claim 2, wherein the first tenant interface comprises the digital tenant interface and the second interface comprises a second digital tenant interface, wherein the digital tenant interface is different from the second digital interface.

5. The enterprise checkout system of claim 4, wherein the second digital interface is a third party tenant interface.

6. The enterprise checkout system of claim 4, wherein the second digital interface is an intermediary tenant interface.

7. The enterprise checkout system of claim 1, wherein the plurality of service APIs are selected from the group comprising: an available to promise API, a cart API, a checkout API, a coupon API, an item API, and item location API, an item price API, an item location price API, a location API, a manufacturer coupon engine API, a payment gateway API, a payment restriction API, a prepaid accounts API, an item restriction API, a promotional engine API, a registry API, a return authorization API, a shipping method API, a gift card API, and a tax rate API.

8. The enterprise checkout system of claim 1, wherein the unified shopping cart is communicatively connected to a plurality of tenant APIs, the plurality of tenant APIs selected from a web checkout API, a marketplace checkout API, a store checkout API, a payment capture API, and a payment web API.

9. The enterprise checkout system of claim 1, where the unified shopping cart is further configured to receive a second request data from the one or more of the plurality of tenant interfaces, wherein the tenant interface receiving the second request data is different than the tenant interface receiving the request data.

10. The enterprise checkout system of claim 9, wherein the unified shopping cart identifies that the request data and the second request data is associated with a same customer.

11. The enterprise checkout system of claim 1, wherein the unified shopping cart maintains a single collection of one or more items.

13. The method of claim 12, wherein the second delivery mode comprises in-store pickup.

14. The method of claim 13, wherein the first request is received from a digital tenant interface.

15. The method of claim 12, wherein the unified shopping cart is communicatively connected to a plurality of service APIs, the plurality of service APIs exposing each of a plurality of corresponding services providing item or transaction attribute data useable in a sales transaction, wherein settling the unified payment transaction further comprises calling one or more of the service APIs.

16. The method of claim 12, wherein the request is generated by the tenant interface in response to a user selecting an item to be added to a shopping cart.

17. The method of claim 12, wherein receiving the request occurs at a first time, and wherein settling the unified payment transaction occurs at a second time after the first time.

18. The method of claim 12, wherein the unified payment transaction is initiated by a third party service provider.

19. The method of claim 12, wherein the unified payment transaction is initiated by the customer at a point of sale tenant interface.

20. The method of claim 12, wherein the first request is received from a digital tenant interface, and the second request is received from a second digital tenant interface, wherein the digital tenant interface is different from the second digital interface.